<!DOCTYPE HTML>
<html lang="zh-CN">


<head>
    <meta charset="utf-8">
    <meta name="keywords" content="Java8新特性, Max|Blog">
    <meta name="description" content="life is a fucking movie">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=no">
    <meta name="renderer" content="webkit|ie-stand|ie-comp">
    <meta name="mobile-web-app-capable" content="yes">
    <meta name="format-detection" content="telephone=no">
    <meta name="apple-mobile-web-app-capable" content="yes">
    <meta name="apple-mobile-web-app-status-bar-style" content="black-translucent">
    <!-- Global site tag (gtag.js) - Google Analytics -->


    <title>Java8新特性 | Max|Blog</title>
    <link rel="icon" type="image/png" href="/favicon.png">

    <link rel="stylesheet" type="text/css" href="/libs/awesome/css/all.css">
    <link rel="stylesheet" type="text/css" href="/libs/materialize/materialize.min.css">
    <link rel="stylesheet" type="text/css" href="/libs/aos/aos.css">
    <link rel="stylesheet" type="text/css" href="/libs/animate/animate.min.css">
    <link rel="stylesheet" type="text/css" href="/libs/lightGallery/css/lightgallery.min.css">
    <link rel="stylesheet" type="text/css" href="/css/matery.css">
    <link rel="stylesheet" type="text/css" href="/css/my.css">

    <script src="/libs/jquery/jquery.min.js"></script>

<meta name="generator" content="Hexo 5.3.0"><link rel="alternate" href="/atom.xml" title="Max|Blog" type="application/atom+xml">
</head>




<body>
    <header class="navbar-fixed">
    <nav id="headNav" class="bg-color nav-transparent">
        <div id="navContainer" class="nav-wrapper container">
            <div class="brand-logo">
                <a href="/" class="waves-effect waves-light">
                    
                    <img src="/medias/logo.png" class="logo-img" alt="LOGO">
                    
                    <span class="logo-span">Max|Blog</span>
                </a>
            </div>
            

<a href="#" data-target="mobile-nav" class="sidenav-trigger button-collapse"><i class="fas fa-bars"></i></a>
<ul class="right nav-menu">
  
  <li class="hide-on-med-and-down nav-item">
    
    <a href="/" class="waves-effect waves-light">
      
      <i class="fas fa-home" style="zoom: 0.6;"></i>
      
      <span>首页</span>
    </a>
    
  </li>
  
  <li class="hide-on-med-and-down nav-item">
    
    <a href="/tags" class="waves-effect waves-light">
      
      <i class="fas fa-tags" style="zoom: 0.6;"></i>
      
      <span>标签</span>
    </a>
    
  </li>
  
  <li class="hide-on-med-and-down nav-item">
    
    <a href="/categories" class="waves-effect waves-light">
      
      <i class="fas fa-bookmark" style="zoom: 0.6;"></i>
      
      <span>分类</span>
    </a>
    
  </li>
  
  <li class="hide-on-med-and-down nav-item">
    
    <a href="/archives" class="waves-effect waves-light">
      
      <i class="fas fa-archive" style="zoom: 0.6;"></i>
      
      <span>归档</span>
    </a>
    
  </li>
  
  <li class="hide-on-med-and-down nav-item">
    
    <a href="/about" class="waves-effect waves-light">
      
      <i class="fas fa-user-circle" style="zoom: 0.6;"></i>
      
      <span>关于</span>
    </a>
    
  </li>
  
  <li class="hide-on-med-and-down nav-item">
    
    <a href="/contact" class="waves-effect waves-light">
      
      <i class="fas fa-comments" style="zoom: 0.6;"></i>
      
      <span>留言板</span>
    </a>
    
  </li>
  
  <li class="hide-on-med-and-down nav-item">
    
    <a href="/friends" class="waves-effect waves-light">
      
      <i class="fas fa-address-book" style="zoom: 0.6;"></i>
      
      <span>友情链接</span>
    </a>
    
  </li>
  
  <li>
    <a href="#searchModal" class="modal-trigger waves-effect waves-light">
      <i id="searchIcon" class="fas fa-search" title="搜索" style="zoom: 0.85;"></i>
    </a>
  </li>
</ul>


<div id="mobile-nav" class="side-nav sidenav">

    <div class="mobile-head bg-color">
        
        <img src="/medias/logo.png" class="logo-img circle responsive-img">
        
        <div class="logo-name">Max|Blog</div>
        <div class="logo-desc">
            
            life is a fucking movie
            
        </div>
    </div>

    

    <ul class="menu-list mobile-menu-list">
        
        <li class="m-nav-item">
	  
		<a href="/" class="waves-effect waves-light">
			
			    <i class="fa-fw fas fa-home"></i>
			
			首页
		</a>
          
        </li>
        
        <li class="m-nav-item">
	  
		<a href="/tags" class="waves-effect waves-light">
			
			    <i class="fa-fw fas fa-tags"></i>
			
			标签
		</a>
          
        </li>
        
        <li class="m-nav-item">
	  
		<a href="/categories" class="waves-effect waves-light">
			
			    <i class="fa-fw fas fa-bookmark"></i>
			
			分类
		</a>
          
        </li>
        
        <li class="m-nav-item">
	  
		<a href="/archives" class="waves-effect waves-light">
			
			    <i class="fa-fw fas fa-archive"></i>
			
			归档
		</a>
          
        </li>
        
        <li class="m-nav-item">
	  
		<a href="/about" class="waves-effect waves-light">
			
			    <i class="fa-fw fas fa-user-circle"></i>
			
			关于
		</a>
          
        </li>
        
        <li class="m-nav-item">
	  
		<a href="/contact" class="waves-effect waves-light">
			
			    <i class="fa-fw fas fa-comments"></i>
			
			留言板
		</a>
          
        </li>
        
        <li class="m-nav-item">
	  
		<a href="/friends" class="waves-effect waves-light">
			
			    <i class="fa-fw fas fa-address-book"></i>
			
			友情链接
		</a>
          
        </li>
        
        
        <li><div class="divider"></div></li>
        <li>
            <a href="https://github.com/zhy2021/zhy2021.github.io" class="waves-effect waves-light" target="_blank">
                <i class="fab fa-github-square fa-fw"></i>Fork Me
            </a>
        </li>
        
    </ul>
</div>


        </div>

        
            <style>
    .nav-transparent .github-corner {
        display: none !important;
    }

    .github-corner {
        position: absolute;
        z-index: 10;
        top: 0;
        right: 0;
        border: 0;
        transform: scale(1.1);
    }

    .github-corner svg {
        color: #0f9d58;
        fill: #fff;
        height: 64px;
        width: 64px;
    }

    .github-corner:hover .octo-arm {
        animation: a 0.56s ease-in-out;
    }

    .github-corner .octo-arm {
        animation: none;
    }

    @keyframes a {
        0%,
        to {
            transform: rotate(0);
        }
        20%,
        60% {
            transform: rotate(-25deg);
        }
        40%,
        80% {
            transform: rotate(10deg);
        }
    }
</style>

<a href="https://github.com/zhy2021/zhy2021.github.io" class="github-corner tooltipped hide-on-med-and-down" target="_blank"
   data-tooltip="Fork Me" data-position="left" data-delay="50">
    <svg viewBox="0 0 250 250" aria-hidden="true">
        <path d="M0,0 L115,115 L130,115 L142,142 L250,250 L250,0 Z"></path>
        <path d="M128.3,109.0 C113.8,99.7 119.0,89.6 119.0,89.6 C122.0,82.7 120.5,78.6 120.5,78.6 C119.2,72.0 123.4,76.3 123.4,76.3 C127.3,80.9 125.5,87.3 125.5,87.3 C122.9,97.6 130.6,101.9 134.4,103.2"
              fill="currentColor" style="transform-origin: 130px 106px;" class="octo-arm"></path>
        <path d="M115.0,115.0 C114.9,115.1 118.7,116.5 119.8,115.4 L133.7,101.6 C136.9,99.2 139.9,98.4 142.2,98.6 C133.8,88.0 127.5,74.4 143.8,58.0 C148.5,53.4 154.0,51.2 159.7,51.0 C160.3,49.4 163.2,43.6 171.4,40.1 C171.4,40.1 176.1,42.5 178.8,56.2 C183.1,58.6 187.2,61.8 190.9,65.4 C194.5,69.0 197.7,73.2 200.1,77.6 C213.8,80.2 216.3,84.9 216.3,84.9 C212.7,93.1 206.9,96.0 205.4,96.6 C205.1,102.4 203.0,107.8 198.3,112.5 C181.9,128.9 168.3,122.5 157.7,114.1 C157.9,116.9 156.7,120.9 152.7,124.9 L141.0,136.5 C139.8,137.7 141.6,141.9 141.8,141.8 Z"
              fill="currentColor" class="octo-body"></path>
    </svg>
</a>
        
    </nav>

</header>

    



<div class="bg-cover pd-header post-cover" style="background-image: url('/medias/featureimages/0.jpg')">
    <div class="container" style="right: 0px;left: 0px;">
        <div class="row">
            <div class="col s12 m12 l12">
                <div class="brand">
                    <h1 class="description center-align post-title">Java8新特性</h1>
                </div>
            </div>
        </div>
    </div>
</div>




<main class="post-container content">

    
    <link rel="stylesheet" href="/libs/tocbot/tocbot.css">
<style>
    #articleContent h1::before,
    #articleContent h2::before,
    #articleContent h3::before,
    #articleContent h4::before,
    #articleContent h5::before,
    #articleContent h6::before {
        display: block;
        content: " ";
        height: 100px;
        margin-top: -100px;
        visibility: hidden;
    }

    #articleContent :focus {
        outline: none;
    }

    .toc-fixed {
        position: fixed;
        top: 64px;
    }

    .toc-widget {
        width: 345px;
        padding-left: 20px;
    }

    .toc-widget .toc-title {
        padding: 35px 0 15px 17px;
        font-size: 1.5rem;
        font-weight: bold;
        line-height: 1.5rem;
    }

    .toc-widget ol {
        padding: 0;
        list-style: none;
    }

    #toc-content {
        padding-bottom: 30px;
        overflow: auto;
    }

    #toc-content ol {
        padding-left: 10px;
    }

    #toc-content ol li {
        padding-left: 10px;
    }

    #toc-content .toc-link:hover {
        color: #42b983;
        font-weight: 700;
        text-decoration: underline;
    }

    #toc-content .toc-link::before {
        background-color: transparent;
        max-height: 25px;

        position: absolute;
        right: 23.5vw;
        display: block;
    }

    #toc-content .is-active-link {
        color: #42b983;
    }

    #floating-toc-btn {
        position: fixed;
        right: 15px;
        bottom: 76px;
        padding-top: 15px;
        margin-bottom: 0;
        z-index: 998;
    }

    #floating-toc-btn .btn-floating {
        width: 48px;
        height: 48px;
    }

    #floating-toc-btn .btn-floating i {
        line-height: 48px;
        font-size: 1.4rem;
    }
</style>
<div class="row">
    <div id="main-content" class="col s12 m12 l9">
        <!-- 文章内容详情 -->
<div id="artDetail">
    <div class="card">
        <div class="card-content article-info">
            <div class="row tag-cate">
                <div class="col s7">
                    
                    <div class="article-tag">
                        
                            <a href="/tags/java/">
                                <span class="chip bg-color">-java</span>
                            </a>
                        
                    </div>
                    
                </div>
                <div class="col s5 right-align">
                    
                </div>
            </div>

            <div class="post-info">
                
                <div class="post-date info-break-policy">
                    <i class="far fa-calendar-minus fa-fw"></i>发布日期:&nbsp;&nbsp;
                    2020-09-21
                </div>
                

                

                
                <div class="info-break-policy">
                    <i class="far fa-file-word fa-fw"></i>文章字数:&nbsp;&nbsp;
                    2.5k
                </div>
                

                
                <div class="info-break-policy">
                    <i class="far fa-clock fa-fw"></i>阅读时长:&nbsp;&nbsp;
                    11 分
                </div>
                

                
                    <div id="busuanzi_container_page_pv" class="info-break-policy">
                        <i class="far fa-eye fa-fw"></i>阅读次数:&nbsp;&nbsp;
                        <span id="busuanzi_value_page_pv"></span>
                    </div>
				
            </div>
        </div>
        <hr class="clearfix">

        
        <!-- 是否加载使用自带的 prismjs. -->
        <link rel="stylesheet" href="/libs/prism/prism.css">
        

        

        <div class="card-content article-card-content">
            <div id="articleContent">
                <h1 id="java8新特性"><a href="#java8新特性" class="headerlink" title="java8新特性"></a>java8新特性</h1><h2 id="生态"><a href="#生态" class="headerlink" title="生态"></a>生态</h2><ul>
<li>Lambda 表达式</li>
<li>函数式接口</li>
<li>方法引用、构造器引用</li>
<li>Stream API</li>
<li>接口中的默认方法/静态方法</li>
<li>新时间日期API</li>
<li>其他新特性</li>
</ul>
<h2 id="新特性"><a href="#新特性" class="headerlink" title="新特性"></a>新特性</h2><ul>
<li>速度更快</li>
<li>代码更少</li>
<li>强大的Stream API</li>
<li>便于并行</li>
<li>最大化减少空指针异常Optional</li>
<li>Hashmap底层的变化</li>
<li>…….</li>
</ul>
<h2 id="Lambda表达式"><a href="#Lambda表达式" class="headerlink" title="Lambda表达式"></a>Lambda表达式</h2><blockquote>
<p>Java 8的一个大亮点是引入Lambda表达式，使用它设计的代码会更加简洁。当开发者在编写Lambda表达式时，也会随之被编译成一个函数式接口。使用Lambda表达式不仅让代码变的简单、而且可读、最重要的是代码量也随之减少很多。</p>
</blockquote>
<p><strong>演变过程</strong></p>
<blockquote>
<p>垃圾代码 –&gt; 策略模式 –&gt; 匿名内部类 –&gt; Lambda表达式</p>
</blockquote>
<p><strong>举例</strong></p>
<ul>
<li><p>匿名内部类</p>
  <pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token class-name">Comparator</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">Integer</span><span class="token punctuation">></span></span> comparator <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Comparator</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">Integer</span><span class="token punctuation">></span></span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
    <span class="token annotation punctuation">@Override</span>
    <span class="token keyword">public</span> <span class="token keyword">int</span> <span class="token function">compare</span><span class="token punctuation">(</span><span class="token class-name">Integer</span> o1<span class="token punctuation">,</span> <span class="token class-name">Integer</span> o2<span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
        <span class="token keyword">return</span> <span class="token class-name">Integer</span><span class="token punctuation">.</span><span class="token function">compare</span><span class="token punctuation">(</span><span class="token number">01</span><span class="token punctuation">,</span><span class="token number">02</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span><span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre>


</li>
</ul>
<ul>
<li><p>Lambda表达式</p>
  <pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token class-name">Comparator</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">Integer</span><span class="token punctuation">></span></span> comparator <span class="token operator">=</span> <span class="token punctuation">(</span>a<span class="token punctuation">,</span>b<span class="token punctuation">)</span> <span class="token operator">-></span> <span class="token class-name">Integer</span><span class="token punctuation">.</span><span class="token function">compare</span><span class="token punctuation">(</span>a<span class="token punctuation">,</span>b<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre>


</li>
</ul>
<p><strong>格式</strong></p>
<ul>
<li><p>无参数无返回值</p>
  <pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">Test02</span> <span class="token punctuation">&#123;</span>
	<span class="token keyword">int</span> num <span class="token operator">=</span> <span class="token number">10</span><span class="token punctuation">;</span> <span class="token comment">//jdk 1.7以前 必须final修饰</span>
    
    <span class="token annotation punctuation">@Test</span>
    <span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">test01</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">&#123;</span>
        <span class="token comment">//匿名内部类</span>
        <span class="token keyword">new</span> <span class="token class-name">Runnable</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
            <span class="token annotation punctuation">@Override</span>
            <span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">run</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">&#123;</span>
                <span class="token comment">//在局部类中引用同级局部变量</span>
                <span class="token comment">//只读</span>
                <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"Hello World"</span> <span class="token operator">+</span> num<span class="token punctuation">)</span><span class="token punctuation">;</span>
            <span class="token punctuation">&#125;</span>
        <span class="token punctuation">&#125;</span><span class="token punctuation">;</span>
    <span class="token punctuation">&#125;</span>

    <span class="token annotation punctuation">@Test</span>
    <span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">test02</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">&#123;</span>
        <span class="token comment">//语法糖</span>
     	<span class="token class-name">Runnable</span> runnable <span class="token operator">=</span> <span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token operator">-></span> <span class="token punctuation">&#123;</span>
         	<span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"Hello Lambda"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
     	<span class="token punctuation">&#125;</span><span class="token punctuation">;</span>
    <span class="token punctuation">&#125;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre>


</li>
</ul>
<ul>
<li><p>有一个参数无返回值</p>
  <pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token annotation punctuation">@Test</span>
<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">test03</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">&#123;</span>
    <span class="token class-name">Consumer</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">String</span><span class="token punctuation">></span></span> consumer <span class="token operator">=</span> <span class="token punctuation">(</span>a<span class="token punctuation">)</span> <span class="token operator">-></span> <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>a<span class="token punctuation">)</span><span class="token punctuation">;</span>
    consumer<span class="token punctuation">.</span><span class="token function">accept</span><span class="token punctuation">(</span><span class="token string">"我觉得还行！"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span></span></code></pre>


</li>
</ul>
<ul>
<li><p>有两个以上的参数，有返回值</p>
  <pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token annotation punctuation">@Test</span>
<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">test04</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">&#123;</span>
    <span class="token class-name">Comparator</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">Integer</span><span class="token punctuation">></span></span> comparator <span class="token operator">=</span> <span class="token punctuation">(</span>a<span class="token punctuation">,</span> b<span class="token punctuation">)</span> <span class="token operator">-></span> <span class="token punctuation">&#123;</span>
        <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"比较接口"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token keyword">return</span> <span class="token class-name">Integer</span><span class="token punctuation">.</span><span class="token function">compare</span><span class="token punctuation">(</span>a<span class="token punctuation">,</span> b<span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token punctuation">&#125;</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre>


</li>
</ul>
<ul>
<li><p>有两个以上的参数，有返回值，并且 Lambda 体中只有1条语句 （大括号 与 return 都可以省略不写）</p>
  <pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token annotation punctuation">@Test</span>
<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">test04</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">&#123;</span>
    <span class="token class-name">Comparator</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">Integer</span><span class="token punctuation">></span></span> comparator <span class="token operator">=</span> <span class="token punctuation">(</span>a<span class="token punctuation">,</span> b<span class="token punctuation">)</span> <span class="token operator">-></span> <span class="token class-name">Integer</span><span class="token punctuation">.</span><span class="token function">compare</span><span class="token punctuation">(</span>a<span class="token punctuation">,</span> b<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span></span></code></pre>


</li>
</ul>
<p><strong>函数式接口</strong></p>
<blockquote>
<p>定义一个接口，只能存放一个方法，并且要添加注解 @FunctionalInterface</p>
</blockquote>
<p><strong>定义一个接口，可以不使用泛型</strong></p>
<pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token annotation punctuation">@FunctionalInterface</span>
<span class="token keyword">public</span> <span class="token keyword">interface</span> <span class="token class-name">MyFun</span> <span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">T</span><span class="token punctuation">></span></span><span class="token punctuation">&#123;</span>
    <span class="token class-name">T</span> <span class="token function">count</span><span class="token punctuation">(</span><span class="token class-name">T</span> t<span class="token punctuation">,</span> <span class="token class-name">T</span> r<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span></span></code></pre>
<p><strong>测试</strong></p>
<pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token class-name">MyFun</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">Integer</span><span class="token punctuation">></span></span> myFun <span class="token operator">=</span> <span class="token punctuation">(</span>x<span class="token punctuation">,</span>y<span class="token punctuation">)</span><span class="token operator">-></span> x<span class="token operator">+</span>y<span class="token punctuation">;</span>
<span class="token class-name">MyFun</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">Integer</span><span class="token punctuation">></span></span> myFun2 <span class="token operator">=</span> <span class="token punctuation">(</span>x<span class="token punctuation">,</span>y<span class="token punctuation">)</span><span class="token operator">-></span> x<span class="token operator">-</span>y<span class="token punctuation">;</span>
<span class="token class-name">MyFun</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">String</span><span class="token punctuation">></span></span> myFun3 <span class="token operator">=</span> <span class="token punctuation">(</span>x<span class="token punctuation">,</span>y<span class="token punctuation">)</span><span class="token operator">-></span> x<span class="token operator">+</span>y<span class="token punctuation">;</span>
<span class="token class-name">MyFun</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">Double</span><span class="token punctuation">></span></span> myFun4 <span class="token operator">=</span> <span class="token punctuation">(</span>x<span class="token punctuation">,</span>y<span class="token punctuation">)</span><span class="token operator">-></span> x<span class="token operator">*</span>y<span class="token punctuation">;</span>

<span class="token class-name">Integer</span> count <span class="token operator">=</span> myFun<span class="token punctuation">.</span><span class="token function">count</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>count<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">Integer</span> count2 <span class="token operator">=</span> myFun2<span class="token punctuation">.</span><span class="token function">count</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>count2<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">String</span> count3 <span class="token operator">=</span> myFun3<span class="token punctuation">.</span><span class="token function">count</span><span class="token punctuation">(</span><span class="token string">"1"</span><span class="token punctuation">,</span> <span class="token string">"2"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>count3<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">Double</span> count4 <span class="token operator">=</span> myFun4<span class="token punctuation">.</span><span class="token function">count</span><span class="token punctuation">(</span><span class="token number">1.1</span><span class="token punctuation">,</span><span class="token number">2.1</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>count4<span class="token punctuation">)</span><span class="token punctuation">;</span>

<span class="token comment">/*
结果是：
    3
    -1
    12
    2.3100000000000005
*/</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre>


<blockquote>
<p>可以发现，函数式接口让我们在实现业务的时候有了很高的自由度，代码书写也更加的紧凑，简便，减少了代码量</p>
</blockquote>
<h2 id="函数式编程"><a href="#函数式编程" class="headerlink" title="函数式编程"></a>函数式编程</h2><p><strong>Java内置四大核心函数式接口：</strong></p>
<table>
<thead>
<tr>
<th align="center"><strong>函数式接口</strong></th>
<th align="center"><strong>参数类型</strong></th>
<th align="center">返回类型</th>
<th align="center"><strong>用途</strong></th>
</tr>
</thead>
<tbody><tr>
<td align="center">Consumer<br/>消费型接口</td>
<td align="center">T</td>
<td align="center">void</td>
<td align="center">对类型为T的对象应用操作：void accept(T t)</td>
</tr>
<tr>
<td align="center">Supplier<br/>提供型接口</td>
<td align="center">无</td>
<td align="center">T</td>
<td align="center">返回类型为T的对象：T get()</td>
</tr>
<tr>
<td align="center">Function&lt;T, R&gt;<br/>函数型接口</td>
<td align="center">T</td>
<td align="center">R</td>
<td align="center">确定类型为T的对象是否满足某约束，并返回boolean值：boolean test(T t)</td>
</tr>
<tr>
<td align="center">Predicate<br/>断言型接口</td>
<td align="center">T</td>
<td align="center">boolean</td>
<td align="center">确定类型为T的对象是否满足某约束，并返回boolean值：boolean test(T t)</td>
</tr>
</tbody></table>
<p><strong>消费型接口</strong></p>
<pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token annotation punctuation">@org.junit.Test</span>
<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">test06</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">&#123;</span>
    <span class="token class-name">Consumer</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">String</span><span class="token punctuation">></span></span> consumer <span class="token operator">=</span> <span class="token punctuation">(</span>x<span class="token punctuation">)</span><span class="token operator">-></span> <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>x<span class="token punctuation">)</span><span class="token punctuation">;</span>
    consumer<span class="token punctuation">.</span><span class="token function">accept</span><span class="token punctuation">(</span><span class="token string">"123"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span></span></code></pre>
<p><strong>提供型接口</strong></p>
<pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token annotation punctuation">@org.junit.Test</span>
<span class="token keyword">public</span>  <span class="token keyword">void</span> <span class="token function">test07</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">&#123;</span>
    <span class="token class-name">Supplier</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">List</span><span class="token punctuation">&lt;</span><span class="token class-name">Integer</span><span class="token punctuation">></span><span class="token punctuation">></span></span> supplier <span class="token operator">=</span> <span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">-></span><span class="token punctuation">&#123;</span>
        <span class="token class-name">List</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">Integer</span><span class="token punctuation">></span></span> list <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">ArrayList</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token punctuation">></span></span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        list<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token keyword">int</span><span class="token punctuation">)</span><span class="token punctuation">(</span><span class="token class-name">Math</span><span class="token punctuation">.</span><span class="token function">random</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">*</span><span class="token number">100</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        list<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token keyword">int</span><span class="token punctuation">)</span><span class="token punctuation">(</span><span class="token class-name">Math</span><span class="token punctuation">.</span><span class="token function">random</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">*</span><span class="token number">100</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        list<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token keyword">int</span><span class="token punctuation">)</span><span class="token punctuation">(</span><span class="token class-name">Math</span><span class="token punctuation">.</span><span class="token function">random</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">*</span><span class="token number">100</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        list<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token keyword">int</span><span class="token punctuation">)</span><span class="token punctuation">(</span><span class="token class-name">Math</span><span class="token punctuation">.</span><span class="token function">random</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">*</span><span class="token number">100</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        list<span class="token punctuation">.</span><span class="token function">add</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token keyword">int</span><span class="token punctuation">)</span><span class="token punctuation">(</span><span class="token class-name">Math</span><span class="token punctuation">.</span><span class="token function">random</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator">*</span><span class="token number">100</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token keyword">return</span> list<span class="token punctuation">;</span>
    <span class="token punctuation">&#125;</span><span class="token punctuation">;</span>

    <span class="token class-name">List</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">Integer</span><span class="token punctuation">></span></span> list <span class="token operator">=</span> supplier<span class="token punctuation">.</span><span class="token function">get</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    list<span class="token punctuation">.</span><span class="token function">forEach</span><span class="token punctuation">(</span><span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token operator">::</span><span class="token function">println</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre>


<p><strong>函数型接口</strong></p>
<pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token annotation punctuation">@org.junit.Test</span>
<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">test08</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">&#123;</span>
    <span class="token class-name">Function</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">Integer</span><span class="token punctuation">,</span><span class="token class-name">Integer</span><span class="token punctuation">></span></span> function <span class="token operator">=</span> <span class="token punctuation">(</span>x<span class="token punctuation">)</span><span class="token operator">-></span> x<span class="token operator">+</span><span class="token number">1</span><span class="token punctuation">;</span>
    <span class="token keyword">int</span> apply <span class="token operator">=</span> function<span class="token punctuation">.</span><span class="token function">apply</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>apply<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre>


<p><strong>断言型接口</strong></p>
<pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token annotation punctuation">@org.junit.Test</span>
<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">test09</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">&#123;</span>
    <span class="token class-name">Predicate</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">String</span><span class="token punctuation">></span></span> predicate <span class="token operator">=</span> x<span class="token operator">-></span> <span class="token string">"predicate"</span><span class="token punctuation">.</span><span class="token function">equals</span><span class="token punctuation">(</span>x<span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>predicate<span class="token punctuation">.</span><span class="token function">test</span><span class="token punctuation">(</span><span class="token string">"1"</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span></span></code></pre>
<p><strong>其他的接口</strong></p>
<p><img src="/home/zhy/.config/Typora/typora-user-images/image-20200922093418137.png" alt="子接口"></p>
<h2 id="方法引用"><a href="#方法引用" class="headerlink" title="方法引用"></a>方法引用</h2><blockquote>
<p>如果Lambda体中的内容有方法已经实现了，我们可以使用方法引用(是Lambda的另一种表达形式)</p>
</blockquote>
<p><strong>语法格式</strong></p>
<ul>
<li><p>对象::实例方法名</p>
  <pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token annotation punctuation">@org.junit.Test</span>
<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">test1</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">&#123;</span>
    <span class="token class-name">Consumer</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">String</span><span class="token punctuation">></span></span> consumer <span class="token operator">=</span> <span class="token punctuation">(</span>x<span class="token punctuation">)</span><span class="token operator">-></span><span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>x<span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token comment">/*
    两者都没有返回值，参数列表也一样
    对象::实例方法名
     */</span>
    <span class="token class-name">Cons</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">String</span><span class="token punctuation">></span></span> consumer2 <span class="token operator">=</span> <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token operator">::</span><span class="token function">println</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>

<span class="token annotation punctuation">@org.junit.Test</span>
<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">test2</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">&#123;</span>
    <span class="token class-name">Users</span> users <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Users</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token comment">/*
    getPassword()的返回类型是String
    函数式接口中抽象方法的返回值也是String
    二者都没有参数
    可以简化lambda表达式
    */</span>
    <span class="token class-name">Supplier</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">String</span><span class="token punctuation">></span></span> supplier <span class="token operator">=</span> users<span class="token operator">::</span><span class="token function">getPassword</span><span class="token punctuation">;</span>
    <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>supplier<span class="token punctuation">.</span><span class="token function">get</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre>


</li>
</ul>
<ul>
<li><p>类::静态方法名</p>
  <pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token annotation punctuation">@org.junit.Test</span>
<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">test3</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">&#123;</span>
    <span class="token comment">// 类:: 静态方法</span>
    <span class="token class-name">Comparator</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">Integer</span><span class="token punctuation">></span></span> comparator <span class="token operator">=</span> <span class="token punctuation">(</span>x<span class="token punctuation">,</span>y<span class="token punctuation">)</span><span class="token operator">-></span><span class="token class-name">Integer</span><span class="token punctuation">.</span><span class="token function">compare</span><span class="token punctuation">(</span>x<span class="token punctuation">,</span>y<span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token class-name">Comparator</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">Integer</span><span class="token punctuation">></span></span> comparator1 <span class="token operator">=</span> <span class="token class-name">Integer</span><span class="token operator">::</span><span class="token function">compare</span><span class="token punctuation">;</span>
    <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>comparator1<span class="token punctuation">.</span><span class="token function">compare</span><span class="token punctuation">(</span><span class="token number">2</span><span class="token punctuation">,</span> <span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre>


</li>
</ul>
<ul>
<li><p>类::实例方法名</p>
  <pre class="line-numbers language-java" data-language="java"><code class="language-java">  <span class="token annotation punctuation">@org.junit.Test</span>
  <span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">test4</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">&#123;</span>
      <span class="token comment">// 类:: 实例方法名</span>
      <span class="token class-name">BiPredicate</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">String</span><span class="token punctuation">,</span><span class="token class-name">String</span><span class="token punctuation">></span></span> predicate <span class="token operator">=</span> <span class="token punctuation">(</span>x<span class="token punctuation">,</span>y<span class="token punctuation">)</span><span class="token operator">-></span>x<span class="token punctuation">.</span><span class="token function">equals</span><span class="token punctuation">(</span>y<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token comment">// 这一个跟上边的 类::静态方法名差不多</span>
      <span class="token class-name">BiPredicate</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">String</span><span class="token punctuation">,</span><span class="token class-name">String</span><span class="token punctuation">></span></span> predicate2 <span class="token operator">=</span> <span class="token class-name">String</span><span class="token operator">::</span><span class="token function">equals</span><span class="token punctuation">;</span>
  <span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre>


</li>
</ul>
<blockquote>
<p>始终要<strong>注意</strong>的是：</p>
<ul>
<li><p>Lambda体黄总调用方法的参数列表和返回值类型，与函数式接口中抽象方法和返回值类型保持一致</p>
</li>
<li><p>如果Lambda参数列表中的第一参数是实例方法的调用着，而第二个参数是实例方法的参数，可以用<code>ClassName::method</code>表示</p>
</li>
</ul>
</blockquote>
<h2 id="构造器引用"><a href="#构造器引用" class="headerlink" title="构造器引用"></a>构造器引用</h2><p><strong>格式</strong></p>
<ul>
<li>ClassName::new</li>
</ul>
<pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token comment">/*
	简单案例，引用无参构造器
*/</span>
<span class="token annotation punctuation">@org.junit.Test</span>
<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">test5</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">&#123;</span>
    <span class="token comment">// className::new</span>
    <span class="token class-name">Supplier</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">Users</span><span class="token punctuation">></span></span> supplier <span class="token operator">=</span> <span class="token class-name">Users</span><span class="token operator">::</span><span class="token keyword">new</span><span class="token punctuation">;</span>
    <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>supplier<span class="token punctuation">.</span><span class="token function">get</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre>


<blockquote>
<p><strong>注意</strong></p>
<ul>
<li>需要调用的构造器的参数列表要与函数式接口中抽象的参数列表保持一致</li>
</ul>
</blockquote>
<p><strong>数组的引用</strong></p>
<pre class="line-numbers language-none"><code class="language-none">@org.junit.Test
public void test6()&#123;
    Function&lt;Integer,String[]&gt; fun &#x3D; (x)-&gt;new String[x];

    &#x2F;*可以变为*&#x2F;
    Function&lt;Integer,String[]&gt; fun2 &#x3D; String[]::new;
&#125;<span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre>


<h2 id="强大的Stream-API"><a href="#强大的Stream-API" class="headerlink" title="强大的Stream API"></a>强大的Stream API</h2><blockquote>
<p>流是数据渠道，用于操作数据源，数组，集合等生产的元素    序列</p>
<ul>
<li>Stream 自己不会存储元素</li>
<li>Stream 不回改变源对象，他们会返回一个持有结果的新的Stream</li>
<li>Stream 操作是延迟执行的。这意味着他们会等到需要结果的时候才执行</li>
</ul>
</blockquote>
<p><strong>步骤</strong></p>
<ul>
<li>创建Stream</li>
<li>中间操作</li>
<li>终止操作</li>
</ul>
<h3 id="创建Stream"><a href="#创建Stream" class="headerlink" title="创建Stream"></a>创建Stream</h3><blockquote>
<p>创建Stream的方法有多种</p>
</blockquote>
<ul>
<li><p>Connection接口下提供的方法stream()或者parallelStream()（并行流）</p>
  <pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token comment">// 通过Connection提供的steam()或者parallelStream()</span>
<span class="token class-name">List</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">String</span><span class="token punctuation">></span></span> list <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">ArrayList</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token punctuation">></span></span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token class-name">Stream</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">String</span><span class="token punctuation">></span></span> stream <span class="token operator">=</span> list<span class="token punctuation">.</span><span class="token function">stream</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span></span></code></pre></li>
<li><p>通过Arrays中的静态方法获取</p>
  <pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token class-name">Users</span><span class="token punctuation">[</span><span class="token punctuation">]</span> users <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">Users</span><span class="token punctuation">[</span><span class="token number">10</span><span class="token punctuation">]</span><span class="token punctuation">;</span>
<span class="token class-name">Stream</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">Users</span><span class="token punctuation">></span></span> stream1 <span class="token operator">=</span> <span class="token class-name">Arrays</span><span class="token punctuation">.</span><span class="token function">stream</span><span class="token punctuation">(</span>users<span class="token punctuation">)</span><span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span></span></code></pre>


</li>
</ul>
<ul>
<li><p>Stream类的静态方法of()获取</p>
  <pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token class-name">Stream</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">Integer</span><span class="token punctuation">></span></span> integerStream <span class="token operator">=</span> <span class="token class-name">Stream</span><span class="token punctuation">.</span><span class="token function">of</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">,</span> <span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre>


</li>
</ul>
<ul>
<li><p>创建无限流</p>
  <pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token class-name">Stream</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">Integer</span><span class="token punctuation">></span></span> iterate <span class="token operator">=</span> <span class="token class-name">Stream</span><span class="token punctuation">.</span><span class="token function">iterate</span><span class="token punctuation">(</span><span class="token number">0</span><span class="token punctuation">,</span> <span class="token punctuation">(</span>x<span class="token punctuation">)</span> <span class="token operator">-></span> x <span class="token operator">+</span> <span class="token number">2</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span aria-hidden="true" class="line-numbers-rows"><span></span></span></code></pre>
<h3 id="中间操作"><a href="#中间操作" class="headerlink" title="中间操作"></a>中间操作</h3></li>
</ul>
<blockquote>
<p>Stream的中间操作和终端操作如下图所示：</p>
</blockquote>
<p><img src="https://img-blog.csdn.net/20180609175507605?watermark/2/text/aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzI4NDEwMjgz/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70" alt="Stream的操作"></p>
<h3 id="切片和筛选"><a href="#切片和筛选" class="headerlink" title="切片和筛选"></a>切片和筛选</h3><blockquote>
<ul>
<li>filter 接收Lambda,从流中排除某些元素</li>
<li>limit 截断流，使元素不超过给定数量</li>
<li>skip(n) 跳过元素，返回一个扔掉了前n个元素的流，如果不足n个则返回一个空流</li>
<li>distinct 筛选，通过流所产生元素的hashCode()和equals()去除重复元素</li>
</ul>
</blockquote>
<pre class="line-numbers language-java" data-language="java"><code class="language-java"> <span class="token annotation punctuation">@Test</span>
 <span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">test1</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">&#123;</span>

     <span class="token class-name">Stream</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">Users</span><span class="token punctuation">></span></span> stream <span class="token operator">=</span> list<span class="token punctuation">.</span><span class="token function">stream</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
     <span class="token comment">/*
     * 中间操作:不会执行任何操作
     * 终止操作:一次性执行全部内容，即"惰性求值"
     
filter(Predicate&lt;? super T> predicate)
满足predicate的条件的会被保留
     * */</span>
     stream<span class="token punctuation">.</span><span class="token function">filter</span><span class="token punctuation">(</span><span class="token punctuation">(</span>e<span class="token punctuation">)</span><span class="token operator">-></span>e<span class="token punctuation">.</span><span class="token function">getPassword</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">equals</span><span class="token punctuation">(</span><span class="token string">"123"</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
     <span class="token punctuation">.</span><span class="token function">forEach</span><span class="token punctuation">(</span><span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token operator">::</span><span class="token function">println</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
 <span class="token punctuation">&#125;</span>

 <span class="token annotation punctuation">@Test</span>
 <span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">test2</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">&#123;</span>
     <span class="token class-name">Stream</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">Users</span><span class="token punctuation">></span></span> stream <span class="token operator">=</span> list<span class="token punctuation">.</span><span class="token function">stream</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
     <span class="token comment">/*
     limit(n) 表示取前n个
     */</span>
     stream<span class="token punctuation">.</span><span class="token function">limit</span><span class="token punctuation">(</span><span class="token number">2</span><span class="token punctuation">)</span>
             <span class="token punctuation">.</span><span class="token function">forEach</span><span class="token punctuation">(</span><span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token operator">::</span><span class="token function">println</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
 <span class="token punctuation">&#125;</span>

 <span class="token annotation punctuation">@Test</span>
 <span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">test3</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">&#123;</span>
     <span class="token comment">/*
     skip(n) 表示跳过前n个，配合limit可以有奇效
     */</span>
     <span class="token class-name">Stream</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">Users</span><span class="token punctuation">></span></span> stream <span class="token operator">=</span> list<span class="token punctuation">.</span><span class="token function">stream</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
     stream<span class="token punctuation">.</span><span class="token function">skip</span><span class="token punctuation">(</span><span class="token number">2</span><span class="token punctuation">)</span>
             <span class="token punctuation">.</span><span class="token function">forEach</span><span class="token punctuation">(</span><span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token operator">::</span><span class="token function">println</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
 <span class="token punctuation">&#125;</span>

 <span class="token annotation punctuation">@Test</span>
 <span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">test4</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">&#123;</span>
     <span class="token class-name">Stream</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">Users</span><span class="token punctuation">></span></span> stream <span class="token operator">=</span> list<span class="token punctuation">.</span><span class="token function">stream</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
     <span class="token comment">/*
     去重操作需要比较二者的hashCode()和equals()，需要重写这两个方法
     */</span>
     stream<span class="token punctuation">.</span><span class="token function">distinct</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
             <span class="token punctuation">.</span><span class="token function">forEach</span><span class="token punctuation">(</span><span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token operator">::</span><span class="token function">println</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
 <span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre>
<h3 id="映射"><a href="#映射" class="headerlink" title="映射"></a>映射</h3><blockquote>
<ul>
<li>map：接收 Lambda ，将元素转换为其他形式或提取信息；接受一个函数作为参数，该函数会被应用到每个元素上，并将其映射成一个新的元素</li>
<li>flatMap：接收一个函数作为参数，将流中每一个值都换成另一个流，然后把所有流重新连接成一个流(类似于collection中的addAll(Collection coll)方法)</li>
</ul>
</blockquote>
<pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token annotation punctuation">@Test</span>
<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">test5</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">&#123;</span>
    <span class="token class-name">List</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">String</span><span class="token punctuation">></span></span> list <span class="token operator">=</span> <span class="token class-name">Arrays</span><span class="token punctuation">.</span><span class="token function">asList</span><span class="token punctuation">(</span><span class="token string">"111"</span><span class="token punctuation">,</span> <span class="token string">"bbb"</span><span class="token punctuation">,</span> <span class="token string">"ccc"</span><span class="token punctuation">,</span> <span class="token string">"awdaw"</span><span class="token punctuation">,</span> <span class="token string">"123"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

    <span class="token comment">/*
    * map 接受一个函数作为参数，该函数会被应用到每个元素上，并将其映射成一个新的元素
    * */</span>
    list<span class="token punctuation">.</span><span class="token function">stream</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
            <span class="token punctuation">.</span><span class="token function">map</span><span class="token punctuation">(</span>str<span class="token operator">-></span>str<span class="token punctuation">.</span><span class="token function">toUpperCase</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
            <span class="token punctuation">.</span><span class="token function">forEach</span><span class="token punctuation">(</span><span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token operator">::</span><span class="token function">println</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

    <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"============================="</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>list<span class="token punctuation">.</span><span class="token function">stream</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
            <span class="token punctuation">.</span><span class="token function">map</span><span class="token punctuation">(</span>users <span class="token operator">-></span> users<span class="token punctuation">.</span><span class="token function">getUsername</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">split</span><span class="token punctuation">(</span><span class="token string">"qweq"</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
            <span class="token punctuation">.</span><span class="token function">distinct</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
            <span class="token punctuation">.</span><span class="token function">forEach</span><span class="token punctuation">(</span><span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token operator">::</span><span class="token function">println</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

    <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"============================="</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token comment">/*
    *  flatMap 把所有流重新连接成一个流，即相同类型的流进行合并
    * */</span>
    list<span class="token punctuation">.</span><span class="token function">stream</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
            <span class="token punctuation">.</span><span class="token function">flatMap</span><span class="token punctuation">(</span><span class="token class-name">TestStream</span><span class="token operator">::</span><span class="token function">getStream</span><span class="token punctuation">)</span>
            <span class="token punctuation">.</span><span class="token function">forEach</span><span class="token punctuation">(</span><span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token operator">::</span><span class="token function">println</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre>
<h3 id="排序"><a href="#排序" class="headerlink" title="排序"></a>排序</h3><blockquote>
<ul>
<li>sorted() 自然排序</li>
<li>sorted(Comparator c) 定制排序</li>
</ul>
</blockquote>
<pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token annotation punctuation">@Test</span>
<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">test11</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">&#123;</span>
    <span class="token class-name">List</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">String</span><span class="token punctuation">></span></span> list <span class="token operator">=</span> <span class="token class-name">Arrays</span><span class="token punctuation">.</span><span class="token function">asList</span><span class="token punctuation">(</span><span class="token string">"111"</span><span class="token punctuation">,</span> <span class="token string">"bbb"</span><span class="token punctuation">,</span> <span class="token string">"ccc"</span><span class="token punctuation">,</span> <span class="token string">"awdaw"</span><span class="token punctuation">,</span> <span class="token string">"123"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token comment">/*自然排序*/</span>
    <span class="token class-name">Stream</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">String</span><span class="token punctuation">></span></span> stream <span class="token operator">=</span> list<span class="token punctuation">.</span><span class="token function">stream</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    stream<span class="token punctuation">.</span><span class="token function">sorted</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
            <span class="token punctuation">.</span><span class="token function">forEach</span><span class="token punctuation">(</span><span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token operator">::</span><span class="token function">println</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

    <span class="token comment">/*定制排序*/</span>
    <span class="token keyword">this</span><span class="token punctuation">.</span>list<span class="token punctuation">.</span><span class="token function">stream</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
            <span class="token punctuation">.</span><span class="token function">sorted</span><span class="token punctuation">(</span><span class="token punctuation">(</span>x<span class="token punctuation">,</span>y<span class="token punctuation">)</span><span class="token operator">-></span> x<span class="token punctuation">.</span><span class="token function">getUsername</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">compareTo</span><span class="token punctuation">(</span>y<span class="token punctuation">.</span><span class="token function">getUsername</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
            <span class="token punctuation">.</span><span class="token function">forEach</span><span class="token punctuation">(</span><span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token operator">::</span><span class="token function">println</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre>
<h2 id="终止操作"><a href="#终止操作" class="headerlink" title="终止操作"></a>终止操作</h2><h3 id="查找与匹配"><a href="#查找与匹配" class="headerlink" title="查找与匹配"></a>查找与匹配</h3><blockquote>
<ul>
<li>allMatch：检查是否匹配所有元素</li>
<li>anyMatch：检查是否至少匹配一个元素</li>
<li>noneMatch：检查是否没有匹配所有元素</li>
<li>findFirst：返回第一个元素</li>
<li>findAny：返回当前流中的任意元素</li>
<li>count：返回流中元素的总个数</li>
<li>max：返回流中最大值</li>
<li>min：返回流中最小值</li>
</ul>
</blockquote>
<pre class="line-numbers language-java" data-language="java"><code class="language-java"><span class="token keyword">public</span> <span class="token keyword">enum</span> <span class="token class-name">Status</span> <span class="token punctuation">&#123;</span>
    FREE<span class="token punctuation">,</span> BUSY<span class="token punctuation">,</span> VOCATION<span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span>

<span class="token annotation punctuation">@Test</span>
<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">test01</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">&#123;</span>
    <span class="token class-name">List</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">Status</span><span class="token punctuation">></span></span> list <span class="token operator">=</span> <span class="token class-name">Arrays</span><span class="token punctuation">.</span><span class="token function">asList</span><span class="token punctuation">(</span><span class="token class-name">Status</span><span class="token punctuation">.</span>FREE<span class="token punctuation">,</span> <span class="token class-name">Status</span><span class="token punctuation">.</span>BUSY<span class="token punctuation">,</span> <span class="token class-name">Status</span><span class="token punctuation">.</span>VOCATION<span class="token punctuation">)</span><span class="token punctuation">;</span>

    <span class="token keyword">boolean</span> flag1 <span class="token operator">=</span> list<span class="token punctuation">.</span><span class="token function">stream</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
        <span class="token punctuation">.</span><span class="token function">allMatch</span><span class="token punctuation">(</span><span class="token punctuation">(</span>s<span class="token punctuation">)</span> <span class="token operator">-></span> s<span class="token punctuation">.</span><span class="token function">equals</span><span class="token punctuation">(</span><span class="token class-name">Status</span><span class="token punctuation">.</span>BUSY<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>flag1<span class="token punctuation">)</span><span class="token punctuation">;</span>

    <span class="token keyword">boolean</span> flag2 <span class="token operator">=</span> list<span class="token punctuation">.</span><span class="token function">stream</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
        <span class="token punctuation">.</span><span class="token function">anyMatch</span><span class="token punctuation">(</span><span class="token punctuation">(</span>s<span class="token punctuation">)</span> <span class="token operator">-></span> s<span class="token punctuation">.</span><span class="token function">equals</span><span class="token punctuation">(</span><span class="token class-name">Status</span><span class="token punctuation">.</span>BUSY<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>flag2<span class="token punctuation">)</span><span class="token punctuation">;</span>

    <span class="token keyword">boolean</span> flag3 <span class="token operator">=</span> list<span class="token punctuation">.</span><span class="token function">stream</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
        <span class="token punctuation">.</span><span class="token function">noneMatch</span><span class="token punctuation">(</span><span class="token punctuation">(</span>s<span class="token punctuation">)</span> <span class="token operator">-></span> s<span class="token punctuation">.</span><span class="token function">equals</span><span class="token punctuation">(</span><span class="token class-name">Status</span><span class="token punctuation">.</span>BUSY<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>flag3<span class="token punctuation">)</span><span class="token punctuation">;</span>

    <span class="token comment">// 避免空指针异常</span>
    <span class="token class-name">Optional</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">Status</span><span class="token punctuation">></span></span> op1 <span class="token operator">=</span> list<span class="token punctuation">.</span><span class="token function">stream</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
        <span class="token punctuation">.</span><span class="token function">findFirst</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token comment">// 如果Optional为空 找一个替代的对象</span>
    <span class="token class-name">Status</span> s1 <span class="token operator">=</span> op1<span class="token punctuation">.</span><span class="token function">orElse</span><span class="token punctuation">(</span><span class="token class-name">Status</span><span class="token punctuation">.</span>BUSY<span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>s1<span class="token punctuation">)</span><span class="token punctuation">;</span>

    <span class="token comment">// 随便获取一个</span>
    <span class="token class-name">Optional</span><span class="token generics"><span class="token punctuation">&lt;</span><span class="token class-name">Status</span><span class="token punctuation">></span></span> op2 <span class="token operator">=</span> list<span class="token punctuation">.</span><span class="token function">stream</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
        <span class="token punctuation">.</span><span class="token function">findAny</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>op2<span class="token punctuation">)</span><span class="token punctuation">;</span>

    <span class="token keyword">long</span> count <span class="token operator">=</span> list<span class="token punctuation">.</span><span class="token function">stream</span><span class="token punctuation">(</span><span class="token punctuation">)</span>
        <span class="token punctuation">.</span><span class="token function">count</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>count<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">&#125;</span><span aria-hidden="true" class="line-numbers-rows"><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></span></code></pre>


<h3 id="归约与收集"><a href="#归约与收集" class="headerlink" title="归约与收集"></a>归约与收集</h3><blockquote>
<ul>
<li>归约：reduce(T identity, BinaryOperator) / reduce(BinaryOperator) 可以将流中的数据反复结合起来，得到一个值</li>
<li>收集：collect 将流转换成其他形式；接收一个 Collector 接口的实现，用于给流中元素做汇总的方法</li>
</ul>
</blockquote>

                
            </div>
            <hr/>

            

    <div class="reprint" id="reprint-statement">
        
            <div class="reprint__author">
                <span class="reprint-meta" style="font-weight: bold;">
                    <i class="fas fa-user">
                        文章作者:
                    </i>
                </span>
                <span class="reprint-info">
                    <a href="/about" rel="external nofollow noreferrer">Max</a>
                </span>
            </div>
            <div class="reprint__type">
                <span class="reprint-meta" style="font-weight: bold;">
                    <i class="fas fa-link">
                        文章链接:
                    </i>
                </span>
                <span class="reprint-info">
                    <a href="https://zhy2021.github.io/2020/09/21/java8-xin-te-xing/">https://zhy2021.github.io/2020/09/21/java8-xin-te-xing/</a>
                </span>
            </div>
            <div class="reprint__notice">
                <span class="reprint-meta" style="font-weight: bold;">
                    <i class="fas fa-copyright">
                        版权声明:
                    </i>
                </span>
                <span class="reprint-info">
                    本博客所有文章除特別声明外，均采用
                    <a href="https://creativecommons.org/licenses/by/4.0/deed.zh" rel="external nofollow noreferrer" target="_blank">CC BY 4.0</a>
                    许可协议。转载请注明来源
                    <a href="/about" target="_blank">Max</a>
                    !
                </span>
            </div>
        
    </div>

    <script async defer>
      document.addEventListener("copy", function (e) {
        let toastHTML = '<span>复制成功，请遵循本文的转载规则</span><button class="btn-flat toast-action" onclick="navToReprintStatement()" style="font-size: smaller">查看</a>';
        M.toast({html: toastHTML})
      });

      function navToReprintStatement() {
        $("html, body").animate({scrollTop: $("#reprint-statement").offset().top - 80}, 800);
      }
    </script>



            <div class="tag_share" style="display: block;">
                <div class="post-meta__tag-list" style="display: inline-block;">
                    
                        <div class="article-tag">
                            
                                <a href="/tags/java/">
                                    <span class="chip bg-color">-java</span>
                                </a>
                            
                        </div>
                    
                </div>
                <div class="post_share" style="zoom: 80%; width: fit-content; display: inline-block; float: right; margin: -0.15rem 0;">
                    <link rel="stylesheet" type="text/css" href="/libs/share/css/share.min.css">
<div id="article-share">

    
    <div class="social-share" data-sites="twitter,facebook,google,qq,qzone,wechat,weibo,douban,linkedin" data-wechat-qrcode-helper="<p>微信扫一扫即可分享！</p>"></div>
    <script src="/libs/share/js/social-share.min.js"></script>
    

    

</div>

                </div>
            </div>
            
        </div>
    </div>

    

    

    

    

    
        <style>
    .valine-card {
        margin: 1.5rem auto;
    }

    .valine-card .card-content {
        padding: 20px 20px 5px 20px;
    }

    #vcomments textarea {
        box-sizing: border-box;
        background: url("/medias/comment_bg.png") 100% 100% no-repeat;
    }

    #vcomments p {
        margin: 2px 2px 10px;
        font-size: 1.05rem;
        line-height: 1.78rem;
    }

    #vcomments blockquote p {
        text-indent: 0.2rem;
    }

    #vcomments a {
        padding: 0 2px;
        color: #4cbf30;
        font-weight: 500;
        text-decoration: none;
    }

    #vcomments img {
        max-width: 100%;
        height: auto;
        cursor: pointer;
    }

    #vcomments ol li {
        list-style-type: decimal;
    }

    #vcomments ol,
    ul {
        display: block;
        padding-left: 2em;
        word-spacing: 0.05rem;
    }

    #vcomments ul li,
    ol li {
        display: list-item;
        line-height: 1.8rem;
        font-size: 1rem;
    }

    #vcomments ul li {
        list-style-type: disc;
    }

    #vcomments ul ul li {
        list-style-type: circle;
    }

    #vcomments table, th, td {
        padding: 12px 13px;
        border: 1px solid #dfe2e5;
    }

    #vcomments table, th, td {
        border: 0;
    }

    table tr:nth-child(2n), thead {
        background-color: #fafafa;
    }

    #vcomments table th {
        background-color: #f2f2f2;
        min-width: 80px;
    }

    #vcomments table td {
        min-width: 80px;
    }

    #vcomments h1 {
        font-size: 1.85rem;
        font-weight: bold;
        line-height: 2.2rem;
    }

    #vcomments h2 {
        font-size: 1.65rem;
        font-weight: bold;
        line-height: 1.9rem;
    }

    #vcomments h3 {
        font-size: 1.45rem;
        font-weight: bold;
        line-height: 1.7rem;
    }

    #vcomments h4 {
        font-size: 1.25rem;
        font-weight: bold;
        line-height: 1.5rem;
    }

    #vcomments h5 {
        font-size: 1.1rem;
        font-weight: bold;
        line-height: 1.4rem;
    }

    #vcomments h6 {
        font-size: 1rem;
        line-height: 1.3rem;
    }

    #vcomments p {
        font-size: 1rem;
        line-height: 1.5rem;
    }

    #vcomments hr {
        margin: 12px 0;
        border: 0;
        border-top: 1px solid #ccc;
    }

    #vcomments blockquote {
        margin: 15px 0;
        border-left: 5px solid #42b983;
        padding: 1rem 0.8rem 0.3rem 0.8rem;
        color: #666;
        background-color: rgba(66, 185, 131, .1);
    }

    #vcomments pre {
        font-family: monospace, monospace;
        padding: 1.2em;
        margin: .5em 0;
        background: #272822;
        overflow: auto;
        border-radius: 0.3em;
        tab-size: 4;
    }

    #vcomments code {
        font-family: monospace, monospace;
        padding: 1px 3px;
        font-size: 0.92rem;
        color: #e96900;
        background-color: #f8f8f8;
        border-radius: 2px;
    }

    #vcomments pre code {
        font-family: monospace, monospace;
        padding: 0;
        color: #e8eaf6;
        background-color: #272822;
    }

    #vcomments pre[class*="language-"] {
        padding: 1.2em;
        margin: .5em 0;
    }

    #vcomments code[class*="language-"],
    pre[class*="language-"] {
        color: #e8eaf6;
    }

    #vcomments [type="checkbox"]:not(:checked), [type="checkbox"]:checked {
        position: inherit;
        margin-left: -1.3rem;
        margin-right: 0.4rem;
        margin-top: -1px;
        vertical-align: middle;
        left: unset;
        visibility: visible;
    }

    #vcomments b,
    strong {
        font-weight: bold;
    }

    #vcomments dfn {
        font-style: italic;
    }

    #vcomments small {
        font-size: 85%;
    }

    #vcomments cite {
        font-style: normal;
    }

    #vcomments mark {
        background-color: #fcf8e3;
        padding: .2em;
    }

    #vcomments table, th, td {
        padding: 12px 13px;
        border: 1px solid #dfe2e5;
    }

    table tr:nth-child(2n), thead {
        background-color: #fafafa;
    }

    #vcomments table th {
        background-color: #f2f2f2;
        min-width: 80px;
    }

    #vcomments table td {
        min-width: 80px;
    }

    #vcomments [type="checkbox"]:not(:checked), [type="checkbox"]:checked {
        position: inherit;
        margin-left: -1.3rem;
        margin-right: 0.4rem;
        margin-top: -1px;
        vertical-align: middle;
        left: unset;
        visibility: visible;
    }
</style>

<div class="card valine-card" data-aos="fade-up">
    <div class="comment_headling" style="font-size: 20px; font-weight: 700; position: relative; padding-left: 20px; top: 15px; padding-bottom: 5px;">
        <i class="fas fa-comments fa-fw" aria-hidden="true"></i>
        <span>评论</span>
    </div>
    <div id="vcomments" class="card-content" style="display: grid">
    </div>
</div>

<script src="/libs/valine/av-min.js"></script>
<script src="/libs/valine/Valine.min.js"></script>
<script>
    new Valine({
        el: '#vcomments',
        appId: '5FkhQebEqGdoNnuL654mv5KM-gzGzoHsz',
        appKey: 'NNEBzCiygD4tBLqHt8diLxda',
        notify: 'true' === 'true',
        verify: 'true' === 'true',
        visitor: 'true' === 'true',
        avatar: 'mm',
        pageSize: '10',
        lang: 'zh-cn',
        placeholder: 'just go go'
    });
</script>

    

    

    

    

    

<article id="prenext-posts" class="prev-next articles">
    <div class="row article-row">
        
        <div class="article col s12 m6" data-aos="fade-up">
            <div class="article-badge left-badge text-color">
                <i class="fas fa-chevron-left"></i>&nbsp;上一篇</div>
            <div class="card">
                <a href="/2020/09/25/jvm02/">
                    <div class="card-image">
                        
                        
                        <img src="/medias/featureimages/11.jpg" class="responsive-img" alt="JVM02">
                        
                        <span class="card-title">JVM02</span>
                    </div>
                </a>
                <div class="card-content article-content">
                    <div class="summary block-with-text">
                        
                            jvm运行时数据区，程序计数器，虚拟机栈，本地方法栈
                        
                    </div>
                    <div class="publish-info">
                        <span class="publish-date">
                            <i class="far fa-clock fa-fw icon-date"></i>2020-09-25
                        </span>
                        <span class="publish-author">
                            
                            <i class="fas fa-bookmark fa-fw icon-category"></i>
                            
                            <a href="/categories/jvm/" class="post-category">
                                    -jvm
                                </a>
                            
                            
                        </span>
                    </div>
                </div>
                
                <div class="card-action article-tags">
                    
                    <a href="/tags/jvm/">
                        <span class="chip bg-color">jvm</span>
                    </a>
                    
                </div>
                
            </div>
        </div>
        
        
        <div class="article col s12 m6" data-aos="fade-up">
            <div class="article-badge right-badge text-color">
                下一篇&nbsp;<i class="fas fa-chevron-right"></i>
            </div>
            <div class="card">
                <a href="/2020/09/21/leetcode-shua-ti/">
                    <div class="card-image">
                        
                        
                        <img src="/medias/featureimages/22.jpg" class="responsive-img" alt="leetcode刷题">
                        
                        <span class="card-title">leetcode刷题</span>
                    </div>
                </a>
                <div class="card-content article-content">
                    <div class="summary block-with-text">
                        
                            算法,leetcode
                        
                    </div>
                    <div class="publish-info">
                            <span class="publish-date">
                                <i class="far fa-clock fa-fw icon-date"></i>2020-09-21
                            </span>
                        <span class="publish-author">
                            
                            <i class="fas fa-user fa-fw"></i>
                            Max
                            
                        </span>
                    </div>
                </div>
                
                <div class="card-action article-tags">
                    
                    <a href="/tags/leetcode/">
                        <span class="chip bg-color">leetcode</span>
                    </a>
                    
                </div>
                
            </div>
        </div>
        
    </div>
</article>

</div>


<script>
    $('#articleContent').on('copy', function (e) {
        // IE8 or earlier browser is 'undefined'
        if (typeof window.getSelection === 'undefined') return;

        var selection = window.getSelection();
        // if the selection is short let's not annoy our users.
        if (('' + selection).length < Number.parseInt('120')) {
            return;
        }

        // create a div outside of the visible area and fill it with the selected text.
        var bodyElement = document.getElementsByTagName('body')[0];
        var newdiv = document.createElement('div');
        newdiv.style.position = 'absolute';
        newdiv.style.left = '-99999px';
        bodyElement.appendChild(newdiv);
        newdiv.appendChild(selection.getRangeAt(0).cloneContents());

        // we need a <pre> tag workaround.
        // otherwise the text inside "pre" loses all the line breaks!
        if (selection.getRangeAt(0).commonAncestorContainer.nodeName === 'PRE') {
            newdiv.innerHTML = "<pre>" + newdiv.innerHTML + "</pre>";
        }

        var url = document.location.href;
        newdiv.innerHTML += '<br />'
            + '来源: Max|Blog<br />'
            + '文章作者: Max<br />'
            + '文章链接: <a href="' + url + '">' + url + '</a><br />'
            + '本文章著作权归作者所有，任何形式的转载都请注明出处。';

        selection.selectAllChildren(newdiv);
        window.setTimeout(function () {bodyElement.removeChild(newdiv);}, 200);
    });
</script>


<!-- 代码块功能依赖 -->
<script type="text/javascript" src="/libs/codeBlock/codeBlockFuction.js"></script>

<!-- 代码语言 -->

<script type="text/javascript" src="/libs/codeBlock/codeLang.js"></script>


<!-- 代码块复制 -->

<script type="text/javascript" src="/libs/codeBlock/codeCopy.js"></script>


<!-- 代码块收缩 -->

<script type="text/javascript" src="/libs/codeBlock/codeShrink.js"></script>


    </div>
    <div id="toc-aside" class="expanded col l3 hide-on-med-and-down">
        <div class="toc-widget card" style="background-color: white;">
            <div class="toc-title"><i class="far fa-list-alt"></i>&nbsp;&nbsp;目录</div>
            <div id="toc-content"></div>
        </div>
    </div>
</div>

<!-- TOC 悬浮按钮. -->

<div id="floating-toc-btn" class="hide-on-med-and-down">
    <a class="btn-floating btn-large bg-color">
        <i class="fas fa-list-ul"></i>
    </a>
</div>


<script src="/libs/tocbot/tocbot.min.js"></script>
<script>
    $(function () {
        tocbot.init({
            tocSelector: '#toc-content',
            contentSelector: '#articleContent',
            headingsOffset: -($(window).height() * 0.4 - 45),
            collapseDepth: Number('0'),
            headingSelector: 'h2, h3, h4'
        });

        // modify the toc link href to support Chinese.
        let i = 0;
        let tocHeading = 'toc-heading-';
        $('#toc-content a').each(function () {
            $(this).attr('href', '#' + tocHeading + (++i));
        });

        // modify the heading title id to support Chinese.
        i = 0;
        $('#articleContent').children('h2, h3, h4').each(function () {
            $(this).attr('id', tocHeading + (++i));
        });

        // Set scroll toc fixed.
        let tocHeight = parseInt($(window).height() * 0.4 - 64);
        let $tocWidget = $('.toc-widget');
        $(window).scroll(function () {
            let scroll = $(window).scrollTop();
            /* add post toc fixed. */
            if (scroll > tocHeight) {
                $tocWidget.addClass('toc-fixed');
            } else {
                $tocWidget.removeClass('toc-fixed');
            }
        });

        
        /* 修复文章卡片 div 的宽度. */
        let fixPostCardWidth = function (srcId, targetId) {
            let srcDiv = $('#' + srcId);
            if (srcDiv.length === 0) {
                return;
            }

            let w = srcDiv.width();
            if (w >= 450) {
                w = w + 21;
            } else if (w >= 350 && w < 450) {
                w = w + 18;
            } else if (w >= 300 && w < 350) {
                w = w + 16;
            } else {
                w = w + 14;
            }
            $('#' + targetId).width(w);
        };

        // 切换TOC目录展开收缩的相关操作.
        const expandedClass = 'expanded';
        let $tocAside = $('#toc-aside');
        let $mainContent = $('#main-content');
        $('#floating-toc-btn .btn-floating').click(function () {
            if ($tocAside.hasClass(expandedClass)) {
                $tocAside.removeClass(expandedClass).hide();
                $mainContent.removeClass('l9');
            } else {
                $tocAside.addClass(expandedClass).show();
                $mainContent.addClass('l9');
            }
            fixPostCardWidth('artDetail', 'prenext-posts');
        });
        
    });
</script>

    

</main>


<script type="text/javascript" src="http://cdn.mathjax.org/mathjax/latest/MathJax.js?config=default"></script>

    <footer class="page-footer bg-color">
    
        <link rel="stylesheet" href="/libs/aplayer/APlayer.min.css">
<style>
    .aplayer .aplayer-lrc p {
        
        display: none;
        
        font-size: 12px;
        font-weight: 700;
        line-height: 16px !important;
    }

    .aplayer .aplayer-lrc p.aplayer-lrc-current {
        
        display: none;
        
        font-size: 15px;
        color: #42b983;
    }

    
    .aplayer.aplayer-fixed.aplayer-narrow .aplayer-body {
        left: -66px !important;
    }

    .aplayer.aplayer-fixed.aplayer-narrow .aplayer-body:hover {
        left: 0px !important;
    }

    
</style>
<div class="">
    
    <div class="row">
        <meting-js class="col l8 offset-l2 m10 offset-m1 s12"
                   server="netease"
                   type="playlist"
                   id="2844914148"
                   fixed='true'
                   autoplay='false'
                   theme='#42b983'
                   loop='all'
                   order='random'
                   preload='auto'
                   volume='0.7'
                   list-folded='true'
        >
        </meting-js>
    </div>
</div>

<script src="/libs/aplayer/APlayer.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/meting@2/dist/Meting.min.js"></script>

    
    <div class="container row center-align" style="margin-bottom: 15px !important;">
        <div class="col s12 m8 l8 copy-right">
            Copyright&nbsp;&copy;
            
                <span id="year">2020-2021</span>
            
            <span id="year">2020</span>
            <a href="/about" target="_blank">Max</a>
            |&nbsp;Powered by&nbsp;<a href="https://hexo.io/" target="_blank">Hexo</a>
            |&nbsp;Theme&nbsp;<a href="https://github.com/blinkfox/hexo-theme-matery" target="_blank">Matery</a>
            <br>
            
            &nbsp;<i class="fas fa-chart-area"></i>&nbsp;站点总字数:&nbsp;<span
                class="white-color">141.4k</span>&nbsp;字
            
            
            
            
            
            
            <span id="busuanzi_container_site_pv">
                |&nbsp;<i class="far fa-eye"></i>&nbsp;总访问量:&nbsp;<span id="busuanzi_value_site_pv"
                    class="white-color"></span>&nbsp;次
            </span>
            
            
            <span id="busuanzi_container_site_uv">
                |&nbsp;<i class="fas fa-users"></i>&nbsp;总访问人数:&nbsp;<span id="busuanzi_value_site_uv"
                    class="white-color"></span>&nbsp;人
            </span>
            
            <br>
            
            <span id="sitetime">载入运行时间...</span>
            <script>
                function siteTime() {
                    var seconds = 1000;
                    var minutes = seconds * 60;
                    var hours = minutes * 60;
                    var days = hours * 24;
                    var years = days * 365;
                    var today = new Date();
                    var startYear = "2020";
                    var startMonth = "2";
                    var startDate = "13";
                    var startHour = "0";
                    var startMinute = "0";
                    var startSecond = "0";
                    var todayYear = today.getFullYear();
                    var todayMonth = today.getMonth() + 1;
                    var todayDate = today.getDate();
                    var todayHour = today.getHours();
                    var todayMinute = today.getMinutes();
                    var todaySecond = today.getSeconds();
                    var t1 = Date.UTC(startYear, startMonth, startDate, startHour, startMinute, startSecond);
                    var t2 = Date.UTC(todayYear, todayMonth, todayDate, todayHour, todayMinute, todaySecond);
                    var diff = t2 - t1;
                    var diffYears = Math.floor(diff / years);
                    var diffDays = Math.floor((diff / days) - diffYears * 365);
                    var diffHours = Math.floor((diff - (diffYears * 365 + diffDays) * days) / hours);
                    var diffMinutes = Math.floor((diff - (diffYears * 365 + diffDays) * days - diffHours * hours) /
                        minutes);
                    var diffSeconds = Math.floor((diff - (diffYears * 365 + diffDays) * days - diffHours * hours -
                        diffMinutes * minutes) / seconds);
                    if (startYear == todayYear) {
                        document.getElementById("year").innerHTML = todayYear;
                        document.getElementById("sitetime").innerHTML = "本站已安全运行 " + diffDays + " 天 " + diffHours +
                            " 小时 " + diffMinutes + " 分钟 " + diffSeconds + " 秒";
                    } else {
                        document.getElementById("year").innerHTML = startYear + " - " + todayYear;
                        document.getElementById("sitetime").innerHTML = "本站已安全运行 " + diffYears + " 年 " + diffDays +
                            " 天 " + diffHours + " 小时 " + diffMinutes + " 分钟 " + diffSeconds + " 秒";
                    }
                }
                setInterval(siteTime, 1000);
            </script>
            
            <br>
            
        </div>
        <div class="col s12 m4 l4 social-link social-statis">
    <a href="https://github.com/blinkfox" class="tooltipped" target="_blank" data-tooltip="访问我的GitHub" data-position="top" data-delay="50">
        <i class="fab fa-github"></i>
    </a>



    <a href="mailto:1181062873@qq.com" class="tooltipped" target="_blank" data-tooltip="邮件联系我" data-position="top" data-delay="50">
        <i class="fas fa-envelope-open"></i>
    </a>







    <a href="tencent://AddContact/?fromId=50&fromSubId=1&subcmd=all&uin=1181062873" class="tooltipped" target="_blank" data-tooltip="QQ联系我: 1181062873" data-position="top" data-delay="50">
        <i class="fab fa-qq"></i>
    </a>







    <a href="/atom.xml" class="tooltipped" target="_blank" data-tooltip="RSS 订阅" data-position="top" data-delay="50">
        <i class="fas fa-rss"></i>
    </a>

</div>
    </div>
</footer>

<div class="progress-bar"></div>


    <!-- 搜索遮罩框 -->
<div id="searchModal" class="modal">
    <div class="modal-content">
        <div class="search-header">
            <span class="title"><i class="fas fa-search"></i>&nbsp;&nbsp;搜索</span>
            <input type="search" id="searchInput" name="s" placeholder="请输入搜索的关键字"
                   class="search-input">
        </div>
        <div id="searchResult"></div>
    </div>
</div>

<script type="text/javascript">
$(function () {
    var searchFunc = function (path, search_id, content_id) {
        'use strict';
        $.ajax({
            url: path,
            dataType: "xml",
            success: function (xmlResponse) {
                // get the contents from search data
                var datas = $("entry", xmlResponse).map(function () {
                    return {
                        title: $("title", this).text(),
                        content: $("content", this).text(),
                        url: $("url", this).text()
                    };
                }).get();
                var $input = document.getElementById(search_id);
                var $resultContent = document.getElementById(content_id);
                $input.addEventListener('input', function () {
                    var str = '<ul class=\"search-result-list\">';
                    var keywords = this.value.trim().toLowerCase().split(/[\s\-]+/);
                    $resultContent.innerHTML = "";
                    if (this.value.trim().length <= 0) {
                        return;
                    }
                    // perform local searching
                    datas.forEach(function (data) {
                        var isMatch = true;
                        var data_title = data.title.trim().toLowerCase();
                        var data_content = data.content.trim().replace(/<[^>]+>/g, "").toLowerCase();
                        var data_url = data.url;
                        data_url = data_url.indexOf('/') === 0 ? data.url : '/' + data_url;
                        var index_title = -1;
                        var index_content = -1;
                        var first_occur = -1;
                        // only match artiles with not empty titles and contents
                        if (data_title !== '' && data_content !== '') {
                            keywords.forEach(function (keyword, i) {
                                index_title = data_title.indexOf(keyword);
                                index_content = data_content.indexOf(keyword);
                                if (index_title < 0 && index_content < 0) {
                                    isMatch = false;
                                } else {
                                    if (index_content < 0) {
                                        index_content = 0;
                                    }
                                    if (i === 0) {
                                        first_occur = index_content;
                                    }
                                }
                            });
                        }
                        // show search results
                        if (isMatch) {
                            str += "<li><a href='" + data_url + "' class='search-result-title'>" + data_title + "</a>";
                            var content = data.content.trim().replace(/<[^>]+>/g, "");
                            if (first_occur >= 0) {
                                // cut out 100 characters
                                var start = first_occur - 20;
                                var end = first_occur + 80;
                                if (start < 0) {
                                    start = 0;
                                }
                                if (start === 0) {
                                    end = 100;
                                }
                                if (end > content.length) {
                                    end = content.length;
                                }
                                var match_content = content.substr(start, end);
                                // highlight all keywords
                                keywords.forEach(function (keyword) {
                                    var regS = new RegExp(keyword, "gi");
                                    match_content = match_content.replace(regS, "<em class=\"search-keyword\">" + keyword + "</em>");
                                });

                                str += "<p class=\"search-result\">" + match_content + "...</p>"
                            }
                            str += "</li>";
                        }
                    });
                    str += "</ul>";
                    $resultContent.innerHTML = str;
                });
            }
        });
    };

    searchFunc('/search.xml', 'searchInput', 'searchResult');
});
</script>

    <!-- 回到顶部按钮 -->
<div id="backTop" class="top-scroll">
    <a class="btn-floating btn-large waves-effect waves-light" href="#!">
        <i class="fas fa-arrow-up"></i>
    </a>
</div>


    <script src="/libs/materialize/materialize.min.js"></script>
    <script src="/libs/masonry/masonry.pkgd.min.js"></script>
    <script src="/libs/aos/aos.js"></script>
    <script src="/libs/scrollprogress/scrollProgress.min.js"></script>
    <script src="/libs/lightGallery/js/lightgallery-all.min.js"></script>
    <script src="/js/matery.js"></script>

    <!-- Baidu Analytics -->

    <!-- Baidu Push -->

<script>
    (function () {
        var bp = document.createElement('script');
        var curProtocol = window.location.protocol.split(':')[0];
        if (curProtocol === 'https') {
            bp.src = 'https://zz.bdstatic.com/linksubmit/push.js';
        } else {
            bp.src = 'http://push.zhanzhang.baidu.com/push.js';
        }
        var s = document.getElementsByTagName("script")[0];
        s.parentNode.insertBefore(bp, s);
    })();
</script>

    
    
    <script async src="/libs/others/busuanzi.pure.mini.js"></script>
    

    

    

    <!--腾讯兔小巢-->
    
    

    

    

    
    <script src="/libs/instantpage/instantpage.js" type="module"></script>
    

</body>

</html>
